The "quality" of NA players is so low so that even you can manage to be on top of the scoreboard there.
With a high ping you cant beat a good player with a good (low) ping in a "fair" 1 vs 1, its that simple, so you have to play "sneaky", be "aware".
Cavalry is great, you can "train" the delay.
Even easier is 2h. Hide & rape, works with every ping. And when you are forced to fight "fair", well, 2h is so overpowered that almost "compensates" your shitty internet connection so that you will be able to kill most shielders and polearms.
Poleaxe spam is imo boring and totally mindless, but its very effective.
Another option would be ranger. Ranger can be done, even with high ping. Once I shot a guy, and about five seconds later I saw him dying. lol (Of course this only works against non-moving targets).